In view of the energy crisis, attempts have been made to reduce heat loss from processing machinery. In the area of paper manufacture or web drying, it is conventional to feed a wet paper web or the like over a series of cylinders which rotate about their axes and wherein means are provided for heating the periphery of the dryer cylinder so as to dry the web during transport. Conventionally, a large amount of heat is lost axially of the machine, that is, by radiation and convection at both ends of the machine dryer cylinder. Attempts have been made to mount thermal insulation material end panels to the cylinders and to thereby restrict convection and practically eliminate thermal radiation at the cylinder ends. The panels may be readily applied to a cylinder while in place, and in such case, the thermal panels normally are constructed of two or more segments, as for instance hemispheric sections. The sections are applied to the cylinder from opposite sides of the shaft mounting the cylinder for rotation, with the end panel sections being joined at their abutting edges by means of joint covers. In order to insure that the thermal panel will continue to overlie the axial ends of the machine dryer cylinders, means have been provided for coupling the face of the panel to the cylinder in a type of disconnect coupling or connection, permitting the end panels to be easily removed for machine maintenance and repair.
One such assembly involves the use of cuplike permanent magnets which are affixed to the face of the thermal insulation material panels with the cup cavities opening outwardly of the panel, and wherein the magnets are sized to the approximate diameter of the bolt heads which project from the end wall of the cylinder drum, such that the magnets are magnetically clamped to the bolt heads (and to the metal end plates for the cylinder). The permanent magnets are spaced on the panel at similar circumferential positions to the bolt heads projecting from the ends of the dryer cylinder such that when assembled, the magnets surround the bolt heads and magnetically lock the thermal insulation material end panel to the axial ends of the dryer cylinder.
While this method of assembly permits ease in removal of the thermal insulation material end panels from the end faces of the dryer cylinder, the coupling is not one which is positive in nature. The retention force is quite small, and there is no assurance that during operation inadvertently the thermal insulation material end panels will become disengaged, eliminating the thermal barrier and possibly interfering with machine operation, or in some cases, resulting in machine malfunction.
It is, therefore, a primary object of the present invention to provide an improved thermal insulation material end panel assembly which essentially prevents convection and radiation heat loss to a dryer cylinder bearing the same.
It is a further object of the present invention to provide an improved thermal insulation material end panel assembly which may be easily mounted and removed from the dryer cylinder, and in which a positive mechanical connection may be achieved with relatively high coupling strength, greatly reducing the possibility of separation of the panel from the cylinder during machine operation.
It is a further object of the present invention to provide an improved thermal insulation material end panel assembly which insures conservation of thermal energy, provides a cooler working environment, and which functions to insure uniform drying completely across the web of material to be dried as it passes over the dryer cylinder bearing the panels at opposite ends.